engine dieing at idle BPV ISV Fuel pump? '91 200 20v

[auditude at cox.net]

I believe this is what was wrong with my 200q20v when I first got it on the road.  I cleaned the ISV and haven't had the problem.  I used throttle body cleaner instead of carb cleaner since the ISV isn't lubed with gas.

Now I have to pull codes to track down the check engine light coming on, particularly after getting off throttle after driving under boost.  Power levels seem to be unaffected.  I suspect the o2 sensor if it can flag the check engine light because it's been doing this oscillating power thing under part throttle, steady state driving.  I'm thinking the o2 sensor is slow and perhaps now has failed.  

Anyway, I also agree that the loud fuel pump isn't abnormal.  I wouldn't mind it if mine was a bit quieter tho'.

Ken

SuffolkD at aol.com wrote:

Gents:
While the BPV may also contribute to it, I've found (in my case) that the ISV 
Idle Stabilization Valve is the reason. Its easy to figure out.  Towards the 
firewall end of the motor at the top of the intake tract is the ISV.  
Disconnect the connector and see if it continues to stall.
Symptoms are stalling after first starting the engine:  having to use the 
throttle to maintain idle.  It will only throw a code when it really 
malfunctions:  Increase the throttle and sluggish acceleration follows.

You can take it out and test it (the solenoid inside) with a 9 Volt battery.
Most people clean it with throttle body cleaner or carb cleaner.

I suspect the buzzing fuel pump is a separate issue, however if its 
contributing to the stalling, your due to be stranded by the side of the road very soon 
as the fuel pumps worn out.  I've seen them buzz from 3 months to 3 
years...................
Keep the tank full of fuel.

Some mentioned adding "mystery oil" (from the FLAPS stores) to the tank.  No 
BTDT and I'm a bit skeptic.
HTH - Scott by BOSTON

From: "Dave Defferding" <>

> Symptoms are classic for a failed TBV (turbo bypass valve) to me.   Check
> Scott M's site regarding replacement.  Not too expensive and quite easy to
> do.
> 
<snip>
> ----- Original Message ----- 
> From: "Jeremiah Curry" <>
> 
> > Howdy all,
> >
> > Lately my '91 200 20v has been dying while I am coasting up to a red light
> > with the clutch depressed.  I don't notice till I go to start up again or
> > look at the tack.  If I notice while I am still driving I can release the
> > clutch and the engine starts fine, if I am stopped the starter starts the
> > engine no problem.  I noticed this afternoon that there is a unusual
> buzzing
> > sound coming from somewhere by my rear wheel wells, is this the fuel pump?
> > and can that cause these symptoms?  Don't know if this matters, but it is
> > ~95 degrees and humid.  Other than that it runs great.